Question

The vectors u and v are parallel if and only if: (choose ALL correct answers)
A. u+v=(1,0,0)
B. u.v=0
C. u.v=|u||v|
D. (u.v)+(v.v)=1
E. none of the above

Answer 1

any ideas?

Answer 2

B. u.v=0

Answer 3

none seem to work ( C is close to working)

Answer 4

Unless one of the choices include cosθ, then you can prove whether 2 vectors parallel or not!
Thus E!

Answer 5

well B is not right because if v.u=0 that means they are perpendicular C is the right answer because the angle between to parallel vectors is zero then cos0=1

Answer 6

the angle can also be \(\pi\)

Answer 7

<1,0> and <-1,0> are parrellel vectors, but (C) does not hold

Answer 8

the angle cant be pi because if it is pi that means each one has different direction

Answer 9

two nozero vectors u, v are parellel is there exists a nonzero constant c such that

u=cv

Answer 10

they don't have to go in the same direction

Answer 11

here is another definition from the web...

Definition for parallel vectors:
Web definitions:
Two vectors are said to be parallel if they have the same or opposite direction or if one of them is the zero vector..
www.maths.usyd.edu.au/u/MOW/vectors/misc/glossary.html

Answer 12

thanks a lot

Answer 13

np